Ruler



H. PRIESS March 2, 1954 RULER Filed May 16, 1951 2 Sheetls-Sheet l musPRHESS JMM Q mm B1 ATTOR NET 5 March 2, 1954 H. PRIESS 2,670,541

RULER Filed May 16, 1951 2 Sheets-Sheet 2 Patented Mar. 2, 1954 UNITEDSTATES PATENT OFFICE RU I ER Hans Priess, Nienburg an der Weser, GermanyApplication May 16, 1951, Serial No. 226,577

1 Claim.

This invention relates to rulers adapted in use to roll over the drawingsheet, the rolling means comprising two rollers mounted on a commonspindle.

The object of the invention is to provide an accurate parallel ruler ofthe above kind i. e. a. ruler parallel movement of which is not affectedby obstruction such as eraser particles or dust which may be present onthe drawing sheet.

With the foregoing object in view in a ruler of the kind referred tomade in accordance with the invention the rollers and spindle aredisposed adjacent the drawing edge of the ruler so. that the lower edgeof said ruler rests on the drawing sheet, and tooth-like projections areprovided on the lower surface of said bottom edge, said projectionsextending perpendicularly to said spindle.

The result of this arrangement is that the movement of the ruler isdirected in such a way as to maintain parallel movement in the eventthat a force acts on either one of the rollers tending to oppose thisparallel movement; which force may be produced, for example, by eraserdust, in the path of one or both of the rollers.

In order further to eliminate as much as possible any action tending tooppose the parallel movement, the peripheral surfaces of the rollers arein addition fluted or grooved in a known way. As a result, any particlesdetached from a rubber eraser can be rendered harmless since they passinto the flutes or grooves of the rollers and in consequence are notrolled over.

The invention is illustrated in the accompanying drawing, in which:

Figure 1 is a plan view of a roller ruler made according to theinvention;

Figure 2 is a cross section taken on line 11-11, Figure 1;

Figure 3 is a detail plan view of a preferred embodiment of the ruler;

Figure 4 is a view in cross section taken on line IV-IV, Figure 3;

Figure 5 is an underneath view of the ruler, and

Figures 6 and 7 are detail views.

The ruler shown in the drawings is provided with two rollers I mountedadjacent to the ends of the ruler on a common spindle 8. The spindle 8is located in a groove 9. As shown in Figur 1 the spindle 8 is mountedin position with the rollers l by screws H], which have conical ends l2engaging in corresponding conical recesses in the rollers.

The spindle 8 and rollers I are not located along the centre of theruler, but on one side of the longitudinal centre line and adjacent tothe drawing edge H.

As shown in Figures 3 and 4 the ruler is provided centrally on its topsurface with a troughshaped depression [4, in which the users fingerscan be laid when the ruler is in use. The depression It is so arrangedthat its longitudinal centre line 15 is disposed below and spacedsomewhat from the spindle 8, the centre line l5 being thereforerelatively widely spaced from the lower edge It of the ruler.

As shown in Figure 5 the bottom underneath edge l6, ll of the ruler,which rests on the drawing sheet is formed with a series of parallelprojections spaced from one another and having sufficient length toextend perpendicularly to the roller spindle, to permit unobstructedmovement of the ruler over any eraser dust that may be present on thedrawing sheet. If the surface l6, H were continuous, undesiredalterations in the position of the ruler could occur during movement ofthe ruler by reason of the eraser dust.

As shown in Figure 6 the rollers I also have a discontinuous peripheralsurface produced by flutes or grooves in this surface, which preventobstruction to the movement of the ruler by any eraser dust which may bepresent on the drawing sheet.

Figure 6 also shows the mounting of the rollers "I and of the spindle 8.The point ll! of the rollers l bears in a boring in a metal angle member[9, which is connected with the ruler by the headed screw 20. The screw20 passes through a slot 2| in the ruler, so that the angle member [9can be adjusted in the longitudinal direction of the ruler.

Figure 7 shows a modified form of roller having a U-shaped periphery.The recessed part la of the roller carries uniformly distributedsighting marks I3. These sighting marks co-operate with a fixed sightingmark on the ruler to indicate the amount of displacement of the ruler.The spacing of the sighting marks l3 on the two rollers can bedifferent, for example to denote displacements of the ruler by onemillimeter and by five millimeters.

The material of the ruler is only of secondary importance for theinvention. The ruler can be made of wood, metal, plastic or the like.

What I claim is:

A ruler fitted with rolling means comprising two rollers and a spindleon which said rolling 3 means are commonly mounted, said rollers beingformed with peripheral grooves and said ruler having a fiat top surfaceformed midway of its length with a finger depression having a lengthcorresponding substantially to the width of a 5 users fingers, saidrollers and said spindle being disposed adjacent the drawing edge of theruler so that the lower edge of said ruler rests on the drawing sheet,and further comprising a series of parallel projections from the lowersurface 10 References Cited in the file of this patent UNITED STATESPATENTS Number Number Name Date Starke Aug. 22, 1911 Quires June 10,1913 Hundley May 28, 1918 Pidgeon Aug. 27, 1918 Johnson Feb. 5, 1924FOREIGN PATENTS Country Date Great Britain Nov. 9, 1889

